Substrates are usually stored in cassettes. The cassettes are loaded to inspection or metrology systems via load ports. The system that may be used for inspection of substrates usually includes a substrate loader. The substrate loader usually has a pre-aligner and a robotic arm that unloads substrates from the cassette and loads (returns) substrates to the cassette. The robotic arm has an end effector that has to contact the substrate.
There are substrates of different types and sizes and till now each substrate needed a different end effector.